2,4,5-T: The United States’ Disappearing Herbicide

Abstract

In 1948, a few years after its development, the pesticide 2, 4, 5-T was registered for use as an herbicide by the U.S. Department of Agriculture (USDA) under provisions of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Farmers immediately recognized its usefulness for killing off broadleaf plants. They relied on it to control undesirable plants in pasturelands, thereby giving desirable grasses a competitive advantage. Rice growers used it to kill weeds in their fields without harming their crop. Foresters also benefited from its many uses: eliminating competing weeds and keeping down brush and shrub undergrowth in coniferous forests. Governments, railroads, and utility companies used it to clear brush from rights-of-way (trails, areas under utility lines, and shoulders of roadways and railroads) without labor-intensive hand clearing. Moreover, it was quick and easy to apply; helicopters and crop duster airplanes could blanket enormous areas with it in a relatively short time. Of course, the Department of Defense gave 2, 4, 5-T its biggest boost by mixing it with 2, 4-D, a related herbicide, to produce Agent Orange, the most famous defoliant of them all.